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Epithelial-specific deletion of 11β-HSD2 hinders Apcmin/+ mouse tumorigenesis.

Cyclooxygenase-2 (COX-2)-derived prostaglandin E2 (PGE2) promotes colorectal tumorigenesis. Glucocorticoids are endogenous and potent COX-2 inhibitors, and their local actions are downregulated by 11β-hydroxysteroid dehydrogenase type II (11β-HSD2)-mediated metabolism. Previously, it was reported that 11β-HSD2 is increased in human colonic and Apc(min/+) mouse intestinal adenomas and correlated with increased COX-2, and 11β-HSD2 inhibition suppressed the COX-2 pathway and decreased tumorigenesis. Because 11β-HSD2 is expressed in Apc(min/+) mouse intestinal adenoma stromal and epithelial cells, Apc(min/+) mice were generated with selective deletion of 11β-HSD2 in intestinal epithelial cells (Vil-Cre-HSD2(-/-) Apc(min/+)). Deletion of 11β-HSD2 in intestinal epithelia led to marked inhibition of Apc(min/+) mouse intestinal tumorigenesis. Immunostaining indicated decreased 11β-HSD2 and COX-2 expression in adenoma epithelia, whereas stromal COX-2 expression was intact in Vil-Cre-HSD2(-/-) Apc(min/+) mice. In Vil-Cre-HSD2(-/-) Apc(min/+) mouse intestinal adenomas, both p53 and p21 mRNA and protein were increased, with a concomitant decrease in pRb, indicating glucocorticoid-mediated G1-arrest. Further study revealed that REDD1 (regulated in development and DNA damage responses 1), a novel stress-induced gene that inhibits mTOR signaling, was increased, whereas the mTOR signaling pathway was inhibited. Therefore, in Vil-Cre-HSD2(-/-) Apc(min/+) mice, epithelial cell 11β-HSD2 deficiency leads to inhibition of adenoma initiation and growth by attenuation of COX-2 expression, increased cell-cycle arrest, and inhibition of mTOR signaling as a result of increased tumor intracellular active glucocorticoids. IMPLICATIONS: Inhibition of 11β-HSD2 may represent a novel approach for colorectal cancer chemoprevention by increasing tumor glucocorticoid activity, which in turn inhibits tumor growth by multiple pathways.

Pubmed ID: 23741059 RIS Download

Mesh terms: 11-beta-Hydroxysteroid Dehydrogenase Type 2 | Adenoma | Animals | Carcinogenesis | Cell Cycle | Cell Line, Tumor | Colonic Neoplasms | Corticosterone | Cyclin-Dependent Kinase Inhibitor p21 | Cyclooxygenase 2 | Disease Models, Animal | Gene Expression Regulation, Neoplastic | Genes, APC | Humans | Intestinal Mucosa | Mice | Mice, Inbred C57BL | Sequence Deletion | TOR Serine-Threonine Kinases | Transcription Factors | Tumor Suppressor Protein p53

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Associated grants

  • Agency: NIDDK NIH HHS, Id: DK51265
  • Agency: NIEHS NIH HHS, Id: P01 ES013125
  • Agency: NIDDK NIH HHS, Id: DK79341
  • Agency: NIDDK NIH HHS, Id: P30 DK079341
  • Agency: NCI NIH HHS, Id: R01 CA122620
  • Agency: NIDDK NIH HHS, Id: P01 DK038226
  • Agency: NIGMS NIH HHS, Id: GM15431
  • Agency: NIDDK NIH HHS, Id: R01 DK095761
  • Agency: NCI NIH HHS, Id: R01 CA162433
  • Agency: PHS HHS, Id: P50 95103
  • Agency: NIGMS NIH HHS, Id: P01 GM015431
  • Agency: NIGMS NIH HHS, Id: P50 GM015431
  • Agency: NIDDK NIH HHS, Id: R01 DK051265
  • Agency: NIEHS NIH HHS, Id: ES13125
  • Agency: NIDDK NIH HHS, Id: DK38226
  • Agency: NIDDK NIH HHS, Id: DK62794
  • Agency: NCI NIH HHS, Id: CA122620
  • Agency: NIDDK NIH HHS, Id: R01 DK062794

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